1. Field of the Invention
The present invention relates to a diazo dyestuff compound, and particularly, a diazo dyestuff compound suitable for use in a black dye composition for ink-jet printing ink, where it can be mix with other dyestuffs and varying components to prepare a black ink-jet printing ink having good light-fastness.
2. Description of the Related Prior Art
In the field of ink-jet printing, the application at present is short of black ink dyestuff components having good light fastness. The U.S. Pat. No. 4,694,302 and U.S. Pat. No. 5,062,892 disclosed black ink dyestuff compositions that are commonly used in the past. One of such is the dyestuff edible black 2, yet poor properties such as light fastness is exposed thus not satisfying the afore printing need; one another is C.I. Direct Black 168 where the dye has the advantage of good light fastness, however it exhibits low solubility thus limited for the use as ink-jet printing dyestuff components. From that in the dyestuff composition for ink-jet printing, methods for providing a dyestuff composition capable of mixing with other dyestuffs or components for the making of black ink composition characterized with good light fastness is an area that requires continuous efforts.